Rhodococcus equi is an emerging opportunistic pathogen in immunocompromised patients. A lungtransplant recipient developed weight loss, nonproductive cough, dyspnea, and somnolence. Computed tomogram showed a pulmonary nodule and pleural changes in the right allograft that was due to R. equi infection. Alteration of cell-mediated immunity is a predisposing risk factor for R. equi infection in humans. Our patient developed R. equi infection soon after a course of high-dose corticosteroids for acute allograft infection and animal exposure. A course of intravenous vancomycin followed by single-agent long-term therapy with oral ciprofloxacin was successful. © 2011 Daedalus Enterprises.